During certain surgical operations and during dental care, a local anesthetic has to be administered to the patient. This anesthesia is limited to the targeted region and in the case of dental care, should be limited to the tooth or teeth to be treated. The anesthetic product is generally administered by injection into the tissues to be anesthetized.
During dermatological treatments in humans or in animals, it is sometimes useful to have a needle designed in order to perform an injection in a safer and less painful way.
During dental treatments, the injection of an anesthetic product is usually performed in the gums in order to produce effects in the peripheral soft tissues. It is then useful to have a needle available with which the considered anesthesia location may be reached as accurately as possible in order to be able to limit the amount of anesthetic product to be administered.
However, and independently of the annoyances which this represents for the patient, the effectiveness of the anesthesia is not always optimum, since the anesthetic product is partly distributed at a distance from the tooth to be treated instead of remaining concentrated therein. Further, the injection needle is often deviated, since it deforms upon penetrating into the tissues, especially in soft tissues.
Indeed, the needles according to the present invention are mainly intended for administering anesthetic products, but moreover also for other applications, for example dermatological applications, where the question is of depositing a pharmaceutical product in a well-specified location of the human or animal body.
Among the different anesthesia techniques, the present invention is more particularly of interest for intraligamentary anesthesia and troncular anesthesia as practiced in dental surgery.
Intraligamentary anesthesia consists of injecting an anesthetic product into the ligaments surrounding the tooth to be treated. The problem posed by intraligamentary anesthesia with conventional needles is the difficulty experienced for having the needle penetrate sufficiently deeply into the ligament. This very often causes even with the finest needles, leaks of anesthetic. In order to find a remedy to this problem, the practitioner tries to push in his/her needle more deeply and most of the time it bends. This imposes a change of needle and a new prick.
Troncular anesthesia is an anesthesia technique of the lower dental nerve before its entry into the dental channel. During the penetration of a needle into a soft tissue, particularly during troncular anesthesias or locoregional anesthesias, the needle is pushed in quite deeply. During its penetration, the conventional needle deforms and follows a curved trajectory which causes the injection to be never exactly performed at the contemplated location. This is a non-negligible failure factor. To find a remedy to this, several solutions have been proposed. It should be known that most dental needles used are of a diameter of 0.4 or 0.5 mm. First, the diameter of the needle needs to be increased in order to increase its rigidity. It is recommended to preferentially use the diameter of 0.51 mm. Conventionally, the inner diameter of this needle is 0.25 mm. It is recommended to use the bi-rotational insertion technique (BRIT), which consists of rotating the needle during the penetration alternately by one half-turn in one direction or the other, this so that the effects of the deviation are canceled out. This handling is rather difficult to perform and only automatic injection syringes allow this.